Chronic pain is a major problem. Twenty-six percent of Americans suffer with chronic pain and approximately 20% of these patients develop chronic pain following surgery. The prevalence of chronic pain after thoracic surgery may be as great as 80%. Few studies have prospectively examined factors associated with pain after thoracic surgery and/or are limited to considering only a few potential covariates of pain. Both thoracotomy and thoracoscopy patients will be included in this study. The long-term goal of this research is to prevent the development of chronic pain after thoracic surgery. The overall objective of this research is to identify patient and surgical factors associated with the development of chronic pain after thoracic surgery. At the end of this 100 subject single-center prospective feasibility study, key covariates and sample size estimation for a larger prospective multi-center trial to determine the predictors of chronic pain after thoracic surgery will be proposed. These objectives will be attained by pursuing the following specific aims: 1. Define prior distributions for pre-operative, intra-operative and post-operative covariates and determine covariates that are univariately associated with pain at 6 months after thoracotomy/thoracoscopy. 2. Identify key covariates of chronic pain 6 months after thoracic surgery with frequentist and Bayesian multivariate logistic regression model selection This research will have a positive impact by identifying risk factors for the third step: clinical intervention trials in high risk patients undergoing thoracic surgery; propose interventions for modifiable predictors and provide clues to etiology of chronic pain after thoracic surgery. The proposed research is innovative because novel Bayesian statistical techniques will be used to prospectively examine individual and joint associations, among diverse groups of predictors of chronic pain after both thoracotomy and thoracoscopy guided by a biopsychosocial model. This contribution will be significant because at the end of the second, larger study, it will be possibl to propose interventions to decrease the prevalence of chronic pain after thoracic surgery. It is also expected that successful completion of the larger study of thoracic surgery patients will shif the field and lead to similar studies of other surgeries with a high prevalence of chronic pain.